In vivo validation of the split intein-mediated split-Cre recombinase system. a Schematic showing the experimental design for electroporating constructs into LoxP-Stop-LoxP-TdTomato E16.5 embryos. b Strong TdTomato expression was observed with native Cre recombinase or when both NCre-IntN and IntC-CCre constructs were electroporated. No TdTomato was observed when only IntC-CCre was electroporated alone. This demonstrated that Cre-mediated recombination occurs only when both NCre and CCre are present. c Schematic diagram of BAC transgenic mice expressing IntC-CCre in forebrain GABAergic neurons. The resultant BAC transgenic mouse was then further crossed with the LoxP-Stop-LoxP-TdTomato reporter line mouse. Scale bar, 20 μm. d Sagittal section from a DLX-CCre-IRES-eGFP mouse showing that IntC-CCre-positive cells were predominantly found in the forebrain. Scale bar, 1 mm. e Venn diagram showing that 83.1% of DLX6-CCre neurons were GABA-positive. Of the CCre+/GABA+ neurons, 36.5% were PV and 41% were SST. f Immunohistochemical analyses showing DLX6-CCre-IRES-eGFP brain sections stained using specific antibodies against GABA, PV and SST. Scale bars, 20 μm (merged) and 10 μm (enlarged).